Electric lighting.



C. P. STEINMETZ.

ELECTRIC LIGHTING.

APPHOATION FILED 3.21, 1900. RENEWED JULY 2a, 1906.

' 942,472.. Patented Dea'Z, 1909.

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. Witnesses Jnventor".

I Charles $beinmetz,

WMQ E J a of the temperature,

human l ensures a STEINMETZ, or scnnnaornnr, new roan, assisnon no enuaann ELECTRIC COMPANY, A GDRPGRATIUN OF NEW YORK,

ELECTRIC LIGHTING.

Application filed April 21, 1800, Serial No. "3,718. Renewed. July To all whom it may concern:

Be it known that l, CHARLES P. STEIN- METZ, a citizen oi the United States, residing at Schenectady, county of Schenectady, Stateof New York, have invented certain new and useful Improvements in Electric Lighting, of which the following is a speci fication.

in a certain prior application for Letters Patent, Serial Number 7265, filed March 5, 1900, I have called attention to the fact that the light from an electric arc, excluding that portion of the light coming direct from the crater, is practically speaking, independent and dependent principally on the nature of the conducting vapor which forms the arc stream, as if the par ticlesof the electrode carried into the arc stream were set into sympathetic vibration by the passage of current therethrough; and

l have called attention to the fact that the ,efiiciency of the are lamp can be greatly increased by using as-electrodes, or'at least by one electrode, a substance which using as H vaporizes at a comparatively low temperature, whereby the temperature-of the arc stream, and therefore the radiation losses, may begreatly reduced, and more light may be'obtained by the expenditure of a given amount of electrical energy. I have fully set forth in the said prior application the fact' that the substance forming the are stream must necessarily be such as to furnish conductingv vapors, and that mercury is, among other substances, particularly well adapted for this purpose; since it volatilizes at low temperature, and furnishes, when used in the manner above described, a light of .very considerable intensity, though the color of that light is not suitable for general application by reason of the marked absence of the longer light waves correspond ing tothe yellow, orange and red. In the said prior application I disclosed and claimed broadly a method of modifying the color of the are from a terminal possessing the char- 'acteristics above set forth, by the addition to the arc stream of copducting vapors which, when exposed to the action of the current flowing through the arc stream, would give forth the light rays necessary either to complete the spectrum, or to modify it in such a manner as to cause any desired color to. predominate. Further, I have shown, in the Specification of Letters Patent.

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said application, that the mercury arc, owing to the poisonous nature of the fumes, and owing to its instability, must be more or less protected and must therefore be surrounded more, or less completely by a glass'or other transparent or translucent envelop,

and that this envelop is attacked by the action of the various-color-modifying substances, and should therefore be artificially protected. Such, protection is' broadly claimed in my above-mentioned application, and in that application there is described and claimed the method of protection, which consists of neutralizing the chemical activity of the color-modifying substances, as by causing them to exist in the arc in the ionized state, the addition of iodin or iodid of mercury, or better, by introducing the color-modifying substances in the state or condition of salts ofone of the halogen group, preferably iodin. I find that the useof the halogens is of special value when the arc exists in a completely closed vessel in which they may be protected from'the moisture of the atmosphere, but when the arc exists in a vessel which is not perfectly air better to make use of the alternative method whichforms the subject of the present invention, as the halogen salts tend to absorb moisture, which interferes with their action and renders it irregular.

My present method utilizes the broad principle of' introducing the color modifying substances, and of protecting them, and

further utilizes the principle of introducing the substances to the are in the ionized state, but differs from the specific embodiment more particularly set forth in the said application in that it protects the inclosure, not by absolutely preventing chemical action tight, i find a which may be accomplished by upon it, but by regulating the nature of such the color, while the silicic radical is also free to attack the glass, the chemical activ- I a building up at another. But the various silica salts thus formed on the inner suriacc oithe tube are transparent, or at least trans' lucent, and the'only eficct is to give to the descent lamps.

inside of the tube a frosted appearance, similar to that of the well-mews irosted incan- This action does not cut down the light to any serious extent, particularly in view or": the very high eificiency of the lamp, and only serves to cause the tube to present the ap earance of a solid source oi uniform an .agreeably-difiused light.

limited to silicates and to glass tubes, but that my invention includes generally the idea of modifying the color by introducing color-modifying substances in the state of salts of one of the general class of acids, as for example glassforming acids, which form, or are capable of forming, the envelop in which-the light-giving substance is contained. Other acids of this class are for instance boric acid etc.

In the drawing attached to this specifics. tion, Figure 1 is a general view of a lamp constructed in accordance with my present inventiomand Fig. 2 is a diagram of circuits, while Fig. 3 is a view of avery simple form of lamp also'embodying my invention.

Referring more particularly to Fi 1, it will be seen that current enters by he ter -;minal E and thence passes to a regulating device L. As this particular lamp is intended for alternating current, this regulating device may well take the form' of a reactive coil with a nearly closed magnetic,

circuit, such as is ordinarily employed in alternating arc lamps The usual taps or connections may be provided for regulating the amount'of this reactance in circuit. From this reactive coil, current passes by the wire M to the mercury electrode D and thence through the arc in the tube B to the upper terminal D which is preferably formed of iron or aluminum. "From this terminal it passes by the collecting 6-5 with meta-silicates, as above fully explained.

spring N1 through the wire M? to the solenold coils N N and thence to'the terminal E It will be seen that these are the ordinary connections of an arc lamp to be operatcd in multiple are on a single-phase alternating circuit. The terminal D is formed, the-lamp illustrated, of mercury covered It is quite clear that I am not necessarily densing chamber 1.

seams v To describe the structureumore in detail,

it maybe said that the support N is screwed to a ca N and that from this ca depend oids' N N=, above rotor-red to, are mounted respectively on theilimbs of this core, and are so connected that the have a tendency to polarizc'inthe same irection the ma n etic circuit formed by the core. A repu sion devicei), which may .consist'of a solid casting of copper, aluminum, or other-suitable material, is pierced with two holes in order thatit may fit over the two limbs of the laminated piece U, and to this repulsion device are attaphed four guides 0 0 two only ofr-whi'clrarei'siiown in the drawing,

which" work throu h suitable openin sun the upper flange of the spools 0 "the solenoid cores N N The upper flange is expanded for this purpose, while the lower flange is of smaller diameter, The upper electrode D is fastened to the repulsion device O, and is so adjusted that the weight of the parts is sufficient, when no current is passing through the lamp, to compress the coil s ring 0', and to cause the lower end of the e ectrode to dip into the mercury at D Z is a dash-pot, serving to steady t'hc' lamp and to prevent pumping. It will be seen that the screw-ring P is attached to the lower plate of the lamp, and that into this ring is screwed the glass con- A suitable washer P of felt or asbestos, is interposed between this condensing chamber and the lower plate. A second screw-ring is fastened to the lower plate of the lamp by the screw-clamp P and into this rin .is screwed the tube l3,

in order to make it possible for the vapors to pass to the condensing chamber.

In order to carry current to the lower terminal of the lamp, and also in order to pro vide for the return. to the lower terminal of the mercury vapors which may escape into the chamber P 1 provide a glass tube P, which is connected by asbestos washers P with an extension from the chamber P and in a similar way is connected with an extension from the lower end of the tube B. Through this tube I pass the wire M; which at its lower portion is covered with an enamel insulation in orderto protect it the mercury vapors. I further prefer tremity M whereby current will pass rvill fall nd drawing,

through the heating coil M and Will tend to maintain the mercury at D at a sui ficientl high temperature.

The operation of this lamp is as follows: The current enters at the terminal E and passes through the self-induction coil M, in the path above described, through the heating coil M to the mercury electrode D 1f suppose the lamp to be just starting into action, it is clear that the Weight of the repulsion device Will have compressed the,

spring 0*, so that the electrode D Will be in contact With the mercury D Current will therefore pass through the solenoids N N and out to the terminal These solenoids will set up lines of force in the core {It-and by virtue ofthe action set forth in a patent to Elihu Thomson, No. 363,186, the repul sion device will tend to rise, carrying with it the electrode D The lamp will, therefore, burn until the are is broken by too great lengthening. This will not occur the me try is at .a sufficiently high temperature, but if it does occur the electrode the action Will be repeated. may be repeated several times, but the mercury will be heated to a sufficient high temperati'ire, and the electrode D will rise to the position shown in the The length of the resultant arc will obviously be regulated by the design of the soleno i 2 N N", the design ofthe reactance coil, the voltage of the circuit, the di of the tube ll, etc. An increase in This final the resistance of the arc will weaken the \ve' ten the repulsive action, '"c to be shortened. The tendency nt current in the branch inas in most commercial arc s position the tube B will be .irillisntglow of light, and the it willbe regulated by introus substances above men- .5 ie portion D The vapors Will end to escape "from the tube B, but they are collected in the condensing chamber P pass back through the tube P 1 find it much better to pass the condensed substance back outside the tube B, than to allow it to trickle down the sides of this tube.

By variously regulating and adjusting the amount of color; modifying substances introduced, and the character of said substances, and by mixing with the said substances some neutral diluting substance, as for example fluorid of calcium, am able to produce any color or shade of light which l may desire, from pure'white to a brilliant red, blue, green, etc. For example, "it I desire to produce a White light I add mixtures of the metac-tilicates of potassium orlithium and sodium, and when I find that the amount of these substances introduced into the arc is so great as to impart to the light too above set forth.

' metals, and though much red or yellow, I may reduce s tendency by the addition of calcium tluorid, as

Whatever the color-tormare carried into mg substances may be, they the arc, and though they may be dissociated, the acid radicals protect theg'la'ss from the the acid, radicals themselves may attack the glass, nevertheless, the glass is completely protected by the fact that the salts formed on the inside of the glass are transparent or, translucent, and as the quantity of available bases is limited, there is always left enough free acid radicals to neutralize the metals. A. modification of the lamp suitable for use With direct current is shown in my prior application referred to. The connections should. be so'a djusted that the mercury electrode is ing to become hotter, where there exists any tendency to a dificrence oi temperature, or with direct current, but even with this provision the upper part of the tube may rise above the boiling point of mercury. This is another reason for preferring the silicate to the iodide with this type of lamp, as the silicates work better at a higher temperature than they do at a very low temperature.

lt'is important in non-exhausted lamps to provide some device for equalizing the pressure, but it best not to allow mercury fumes to escape from the lamp. I am able to accomplish these objects by the tube 'l, which is inserted in an opening in the lower plate N and registers with a round or crescent-shaped opcningin the Washer P and with a corresponding opening or recess in the upper Wall of the chamber P This tube eXt-endsvertically upward, being bent aroundthe lamp mechanism. It allows air to escape from or to reenter the chamber l but the mercury vapors, which are very heavy, will not rise to the top, but will be condensed on the sides and Will trickle back to the condensing chamber, and thence through the tube P to the lower electrode IF. I

The lamp shown in -Fig. ills of that class in which the arc exists between mercury or equivalent electrodes covered with silica salts, in a rarefied atmosphere of air, or preferably hydrogen, argon or helium, at say 1 min. pressure. T he arc is formed by exposing the lamp to hi h voltage, and the action Will be readily un erstood byvvhat has preceded. Such lamps are Well adapted to constant current circuits. What I claim as new and desire to scour by Letters Patent of the United States, is,

1. The method or modifying the color of the light from an arc existing Within a transparent or translucent envelop, which consists in introducing into the are a colormodifying substance in the condition of a salt of one of the general class of acids forming, or capable of forming, the envelop.

2. The method which consists in causing the one tendegg sympathetic light-giving oscillations in a transparent or translucent envelop, and continuously associating and dissociating the inner Wall of the envelop without destroying its translucency. I

3. The method which consists in causing sympathetic light-giving oscillations of con ducting vapors in a transparent or translucent envelop, and continuously associating and dissociating the inner wall of the envelop without destroying its translucency.

l. The method of protecting a transparent or translucent substance in the presence of active chemicals, which consistsin introducing said chemicals as salts of acids forming with the materials of the transparent substance a transparent or translucent substance.

The method of producing light which consists in generating an electric arc in a glass inclosure, and introducin to the arc metallic salts of silica acid radicals.

6. The method of generatinglight from electric. energy, which consists in creating an electric arc in a glass inclosure between substances one of which, at least, vaporizes at low temperature, and introducin colormodifying metals as salts of glass-forming acids.

7. The combination in an arc lamp, of an envelop, a color modifying substance which may attack the envelop without destroying its translucency, and electrodes in said envelop.

eaaava existing as a salt of an acid which when united with theenvelop will form a transparent or translucent product. i

9. In a mercury arc lamp, a glass inclosure for the are, and color-modifying means consisting of a metallic meta-silicate salt;

10. In a mercury arc lamp, a glass inclosure for the arc, and a color-modifying means consisting of one or more meta'silicates of alkaline metals' 11.,ln a mercury arc lamp, a glass inclosure for the arc, and a color-modifying means consisting of meta-silicate of alkaline metal mixed with a diluent substance.

12. In a mercury arc lamp, a glass inclosure for the arc, and a color-modifying means consisting of meta-silicate of alkaline metal mixed with a calcium fiuorid.

13. In a mercury arc lamp, a hermetically sealed glass inclosure for the arc, electrodes one at least of which is liquid, and a colormodifying substancein said inclosure which I may attack said inclosure without destroying its translucency.

In witness whereof I have hereunto set my hand this 18th day of April, 1900.

CHARLES P. STEINMETZ.

Witnesses:

BENJAMIN B. HULL, ALEX F. MACDONALD. 

